Drawing machine or layout table



April 25, 1944. o. c; HEDIN 2,347,558

DRAWING MACHINE OR LAY-OUT TABLE Filed Sept. 21, 1942 5 Sheets-Sheet 1INVEN TOR.

as? C flea/N Ap 25, 1944- o. c. HEDIN 2,347,558

DRAWING MACHINE OR LAY-OUT TABLE Filed Sept. 21, 1942 5 Sheets-Sheet 2IN V EN TOR.

MWM

April 1944- o. c. HEDlN 2,347,558

' DRAWING MACHINE on LAY-OUT TABLE Filed Sept. 21, 1942 5 Sheets-Sheet 4April 1944- o. c. HEDIN 2,347,558;

97 Q0 INVENTOR. I

k 15 BY Oscne C. H501 WQW Patented Apr. 25, 1944 A Oscar C. Hedin,Cleveland Heights, Ohio, assign- I or to The Weldon Tool Company,Cleveland, 7 Ohio, a corporation of Ohio Application September 21, 1942,Serial No. 459,102

28 Claims.

This invention relates to a drawing machine or lay-out table by whichdrawings requiring extreme accuracy can be made. By way of example, itmight be stated that the invention is useful in producing large scaledrawings of tools or the like which are to be ground or machined andwhich drawings can be applied to the screen of an optical inspectionsystem and on which screen a shadow of the tool being ground or checkedis projected for comparison with the drawing. The invention may bebriefly summarized as consisting of certain novel features ofconstruction and combinations and arrangements of parts which will bedescribed in the specification. and set forth in the appended claims.

In the accompanying sheets of drawings showing a preferred embodiment ofthe invention,

Fig. l is a front elevation of the machine;

Fig. 2 is a top plan view of the same;

Fig. 3 is an enlarged perspective sectional view illustrating one of thescales of the machine with its saddle and associated slide, this sectionbeing taken substantially on the line 3-3 of Fig. 2;

Fig. 4 is an enlarged perspective sectional view showing another scaletogether with the saddle, slide and scriber associated therewith, thissection being taken substantially on the line 4-4 of Fig. 2;

Fig. 4a is an enlarged detached perspective view of the slide whichcarries the scriber, the slide being shown in section;

Fig. 4b is a view on an enlarged scale of the end of the scriber orstylus; I

Fig. 5 is another enlarged perspective sectional view of the first scaletaken substantially on the line 55 of Fig. 2;

Fig. 6 is an enlarged perspective view taken as "indicated by line 6-6of Fig. 2 and showing a portion of the circular rotatable table with itsannular scale and "the vernier associated therewith;

Fig. 7 is a view on-an enlarged scale taken as indicated by line 1- 'Iof Fig. 2 and showing a clamp provided on the carriage for cooperationwith the slide which is movable along the second Fig. 11 is an elevationof a microscope which is used interchangeably in place of the scriberassembly to accurately locate desired points on the drawing;

Fig. 12 is a partial 'plan view on an enlarged scale showing a trammeldevice applied to the slide of the firstscale; and

' Fig. 13 is a partial sectional view taken substantially On line l3-"l3of Fig. 12 to further illustrate the trammel device.

Referring now to the drawings in greater detail, I0 represents a basewith supporting feet II which rest on the floor. Secured to the top ofthe base "I is a spider I: which, as best shown in Fig. 2, comprisesfour laterally projecting arms Hi, the ends of which are turnedoutwardly toward opposite sides of the machine, as shown at l3a in Fig.2. Braces l4 connect opposite pairs of arms I3 to provide a rigidsupporting structure. To the outer bent ends of the spider arms l3 aresecured two parallel rails I 5 to one of which is'secured a long way l6which extends practical- 1y the full length of its rail and to the otherof the rails is secured a shorter way I1.

A rotatable circular table It is located between the spaced ways l6 andI1, and, as will be described in greater detail hereinafter, is adaptedto support the paper, plate or the like on which the drawing is to bemade. The table has a depending central sleeve portion l9 surrounding aspindle 20 which projects upwardly from the base In above the spider I2.The table is rotatably supported by bearings 2| interposed between thesleeve and spindle.

The ways I 6 and I! have inverted V-shaped top portions or ridgessupporting a carriage 22 for movement forwardly and backwardly over thetable IS. The carriage is slidable on the ways and is supported thereonby a pair of bronze shoes lBa engaging the long way l6 and a singlebronze shoe Ila (see also Fig. 10) engaging the shorter way l1. Asshownin Fig. 2, the left end of the carriage is of a triangularconstruction for maximum rigidity, this being obtained by providing arigid connecting bar 22a which extends in an acute angular relationbetween the left end of the bar portion 22b of the carriage and the bodyportion 220 thereof.

As shown in Fig. 2, mydrafting-machine is provided with two straight orlineal scales 23 and 24 which are calibrated in inches and are arrangedto extend at right angles to each other. The scale 23 is located on thebody portion 220 of the carriage and is movable therewith over the tableIt. The scale 24 extends along the shorter way I! and is fixed orstationary.

For mounting the scale 23 on the body portion 22c of the carriage,I'provide the latter with a saddle 25 having a longitudinal groove 26 inwhich this scale is fixed (see Fig. 4). The sides of the saddle projectlaterally as longitudinally extending flanges having V-shaped edges .21.The scale 24 is similarly mounted on the front rail l by providing thelatter with a saddle 28 having a groove 23in which this scale is fixed(see Figs. 3 and .The sides of the saddle 28 also project laterally aslongitudinally extending flanges having V-shaped edges 36.

For making use of the scale 23, I provide the same with a slide 3| whichis movable therealong and which carries a vernier 32 in a position tocooperate with the scale. The slide 3| also carries a scriber assembly33 which will be presently described and which includes a scriber 34(see Fig. 4) for engagement with the paper or plate during movement ofthe slide along the scale 23. The extent of movement which the' slide 3|is permitted along the scale 23, and hence the length of line to bedrawn by the scriber 34, is determined by two stops 35 and 36 which aremovable along.the saddle 25 and are adapted to be clamped at the desiredsetting by the screws 31. The slide 3| and the stops 35 and 36 havegrooved sides which slidably engage the V-edges of the saddle 25. Theslide 3| also has a clamping screw 33 by which it can be locked to thesaddle 25 at a selected point along the scale 23 whenever this may bedesirable.

The scriber assembly 33 includes a bushing 39 which fits in, and extendsthrough, an opening 3|a in an arm 3|b of the slide 3|. The scriber bodyor holder 40 is slidable and rotatable in the bushing and its lower endembodies a chuck 4| which holds the scriber 34. In this instance thescriber is in the form of a stylus, but it should be understood that bya scriber is meant anything by which the drawing may be delineated, suchas a pencil, pen or stylus.

The upper end of the bushing 39 is provided with two axially extendingslots 42 and 43 which are spaced apart 90 and a relatively shallow slot44 located between the first two slots. The scriber body 40 carries aradial pin 45 which, when engaged in the shallow slot 44, holds thescriber body in a relatively elevated neutral or inoperative position sothat the scriber 34 will not contact the drawing. When the pin is movedinto one or the other of the slots 42 and 43, the scriber will rest onthe drawing and may be held thereagainst by a suitable weight (notshown) applied to the reduced stem 46 on the upper end r of the scriberbody 40. As shown in Fig. 4b, the end of the stylus is in the formof apointed pyramid, and when the pin 45 engages in one or the other of theslots 42 and 43, the stylus will be so held that one of its flatpyramidal faces 41 is at 90 to the direction of the drawing or scribingstroke so as to produce a clear, sharp line on the drawing.

The bushing 33 of the scriber assembly 33 is provided with a collar 43which seats against the arm 3lb of the slide 3| for supporting theassuch clamping engagement with the collar by first moving the barendwise on the headed pin 53 toward the bushing 33 and then lifting theouter end of the bar by means of the thumb screw 54 which extendsthrough a threaded opening of the bar. causes the bar 52 to fulcrum onthe pin 53, thereby pressing the forked end-5| against the collar 43.When the scriber assembly is to be removed from the slide 3|, the thumbscrew 54 is rotated in the opposite direction to lower the bar sembly inthe opening 3|a. The collar 48 may and release the clamping pressure ofthe forked end. The bar can then be moved endwise on the pin 53 towithdraw the forked end from the bushing 39.

For cooperation with the scale '24, I provide a slide 55, as shown inFigs. 2 and 3, which is movable along the V-edges 30 of the saddle 28and carries a vernier 56 and a clamping screw. 51 by which the slide canbe clamped-to the saddle at the desired setting along the scale. Thescale 24 is also provided with a clamp 53 which is movable along thescale and is adapted to be clamped to the saddle 28 by means of thescrew 59. The clamp 56 serves as a stop for limiting the movement of thecarriage 22 along the ways in the left-hand direction.

When the slide has been properly positioned along the scale 24 by meansof the vernier '56 and clamped in place by turning the handle connectedto the screw 51, the carriage 22 is moved forwardly (to the right) up tothe slide 55 and is locked thereto by a latch 60 which is carried by theadjacent end of the carriage, the latch being normally held in elevatedposition by a spring 6|. The locking action is obtained in the followingmanner: The latch 60 has a downturned jaw 66a which the operator willlower into the vernier opening of the slide 55. The operator will thenswing the lever 52 which is connected to an eccentric 63 so as to pullthe jaw 60a against the inner side of the vernier opening. To releasethe carriage 22 from the slide 55, the operator will simply reverse theposition of the eccentric 63, whereupon the spring 6| will elevate thelatch 60. v

It might be stated in passing that a magnifying glass, shown at 64 inFig. 1, may be employed with either the vernier 32 or the vernier 56,the magnifying glass being removable and so shaped that it can beapplied to either the slide 3| or the slide 55.

Reverting to the turntable l3, this member is preferably constructed asa phosphor-bronze plate whose upper face provides a smooth surface onwhich the sheet material for the drawing (not shown) is secured bypieces of tape or other appropriate means. This sheet material on whichthe drawing is to be made or delineated may be paper, cloth, anemulsified plate, or even a metal plate. The outer edge of the turntableis provided with a circular scale 65 which is graduated in degrees andextends for the full periphery of the table.

A fixed arcuate vernier 66, preferably readable in minutes, isassociated with the graduated edge of the turntable I 8. This vernier ismounted on an extension 51 (see Figs. 2 and 6) which is secured to thefront rail l5 at the right-hand end of the stationary scale 24. For usewith the vernier 56 and the scale 65 of the turntable, I provide anadjustable radial reference line 68 which enables the turntable to betset very accurately. This reference line is scribed on a transparentmedium 69 which is carried by a holder 10 The lifting action of thescrew 54 extension 14 on the holder 18 and bearsagalnst the upper sideof a slot 15 provided in the vernier support 81. A screw18- which at itslower end normally bears upon the short plate 13 retains the holder 18with thereferenc'e line 88 thereon in agiven position. By loosening thescrew 18, i the reference line and its hol'der can be moved along thearc-shaped groove H and the arcshaped groove 15.

- After the turntable i8 is adjusted, itis tightly clamped in position,and this is accomplished by the following means: Behind the support 81for the vernier 88 is pivoted a lever '11 (see particularly Figs. 8 and9), the rear end of the lever being shown in Fig. 6. At the free end ofthe lever is a O-shaped floating clamp 18, shown in Figs'. 6, 8, and 9,which is carried by the lever and overlaps the top and bottom of theturntable and extends about its outer edge. On the underside of the topof the clamp is a phosphor-bronze plate I9 which is adapted to be pulledinto ongagement with the top surface of the turntable, and on the lowerside of the clamp is a clamping block 80 which is adapted tobesimultaneously lifted into engagement with the lower side of theturntable. This clamp is adapted to be actuated by a screw'8i with anupstanding reduced portion 82 (see Fig. 9) which at its upper end isadapted to engage a depending lug 83 of the block 88. In Fig. 8 theclamp 18 is shown in released position, at which time the pin 8| of theclamp is held in engagement with a stop pin 85 projecting from thevernier support 61 by the action of the spring 86 (see Fig. 9) on thelever 11. After the turn table has been adjusted to a given position,the screw BI is turned so as to move the clamp 18 downward with thephosphorbronze plate 19 thereof engaging the top of the turntable andthe block 80 simultaneously engaging the lower side of the turntable,thereby locking theturntable against rotation and, incidentally, causingseparation of the pins 84 and 85. This clamping action is designed to bepositive and at the same time to cause no stress and resultantdistortion of the turntable on its bearings.

employ a microscope, such as shown in Fig. 11, to locate points on adrawing. This microscope has a conventional pair of cross lines notshown) which are carried by an ocular disk 88. To use the microscope,the scriber assembly 33 is re-.

moved from the opening 3la of the slide 8i and the microscope 81isplacedin this opening so that the collar 89 rests on the arm Nb of theslide. The microscope is retained in the opening 3Ia by the clampingaction of the bar 52 against the collar 89. Then the carriage 22 and theslide 3| with the microscope thereon can be co-ordinately moved over thedrawing until the cross lines on the ocular disk 88 are in opticalcoincidence with the desired point, such location usually beingdetermined by observation of lines previouslyv on the drawing thevernier 32.

In using my improved drawing machine, straight lines can be scribed onthe drawing by moving the slide 3| along the scale 23 after this scalehas been appropriately located at the deor by employment of sired pointover the table i8. Other straight lines can be drawn at right angles tothe first lines either by moving the carriage 22 bodily over the tableI! after the slide 8| has been appropriately located on the scale 23 orby first rotating the table through 90 and then moving the slide 8ialong the scale 23 after the scale 23 has been located at the desiredpoint over the drawing by movement of the carriage 22. Straight linesextending at angles other than 90 to the first straight .lines can alsobe drawn by rotating the Under certain circumstances, it is desirable toI table I8 through the necessary angular distance and then moving theslide and scriber assembly 33 along the scale 23. when circles or otherarcuate lines are to be scribed on the drawing, this can be accomplishedin two ways. One way is to shift the paper or plate on which the drawingis being made to bring the center of the desired arc or circle exactlyon the center or rotation axis of the table l8. The carriage 22 and theslide 3! are then appropriately moved to bring the scriber 34 at thedesired radial distance from the center of the table, whereupon thetable is rotated through the necessary angular distance to cause thedesired are or circle to be scribed on the drawing.

The second way of drawing arcs or circles is by the use of a trammeldevice which is illustrated in Figs. 12 and 13 of the drawings. Thistrammel device comprises a beam or arm in the form of a saddle acarrying 'a graduated scale 90 and a slide 9i movable along such scaleand having a vernier 92 thereon. The slide*9l is similar to the slide 3|in that it includes a clamping screw 93, similar to the. screw 38, bywhich it can be locked at a desired position along the scale and alsohas an arm portion 94, corre- .sponding with the arm portion 3ib, and inthe opening 95 of which the scriber assembly 33 can be mounted as shownin Fig. 13. The inner end of the saddle 90a carries an arm 96 havingthereon 'a pivot pin 91 adapted to be engaged in the opening 3ia of theslide 3i after the scriber assembly 33 (or microscope 81') has beenremoved from such opening. After the trammel device has been mounted onthe slide 3|, the axis of the pivot pin 91 previously having beenbrought into exact coincidence with the center of the are or circle tobe scribed by appropriate mechanically and/or optically controlledmovements of the carriage 22 and the slide 3| and the slide 9| havingbeen adjusted to bring the scriber 34 at the proper radial distance fromsuch center, the trammel device is swung about the axis of the pivot pinfor the necessary angular distance to scribe the desired are.

To prevent deflection or sagging of the trammel device due to the weightthereof, I may provide this device with an auxiliary support which isengageable with the surface 015 the table Hi. This auxiliary support maycomprise a slide 98 which is shiftable along the saddle 98a and has onor more headed stems 99 glidingly engaging the surface of the table. Theslide 98 may also b provided with a clampingscrew [00 by which it may belocked to the saddle 99a at a desired point thereof.

For the convenience of the operator, I may on paper, emulsified or metalsurfaces, of the most complicated mathematical or geometrical nature,with a flexibility of method and to a degree of accuracy heretoforeunattainable with such devices.

The scriber (pen, pencil, or stylus) point and microscope optical axisare common, due to their mechanically accurate interchangeability as tooperating position. By means of the sliding membersstraight lines may begenerated or drawn. By means ofappropriate scales and verniers the linesmay be accurately located in terms of thousandths of an inch. Thesliding members in combination with the appropriate scales, verniers andstops permit drawing lines of predetermined lengthand position, trulyparallel and spaced to a repeatable accuracy of thousandths of an inch.Employment of the 90- degree co-ordinately sliding members permits linesto be drawn, accurately located and/or spaced, at'right angles one toanother. The rotatable table with its 360 graduated circle andassociated angular vemier permits the drawing of lines at other variousmutual angles, determinable and repeatable in increments of 5 minutes ofarc. The rotatable table may be used for the scribing of circular linesabout a center common to the axis of rotation of the table. By means ofthe microscope which, by means of the Vernier slides, may be positionedwith its optical axis common to the axis of rotation of the table,predetermined or laid-out locations on the drawing is to be made, aframework, a carriage movable on said framework over the table, saidcarriage having a scale and a scriber-canying slide movable along saidscale, a stationary scale supported by the framework, 9. vemier slidemovable relatively to said stationary scale, and means for clamping thecarriage to said vernier slide;

4. A drawing machine or lay-out table comprising a base, a tablesupported by said base and adapted to receive the material on which thedrawing is to be made, a framework provided with ways, a carriagemovable on said ways over said table, said carriage having a scale, ascriber slide movable along said scale, a stationary scale supported bysaid framework, a vemier slide movable relative to'said stationaryscale, and a the drawing may also be positioned common to the axis oftable rotation for the purpose of scribing circular lines about saidlocation points, the radii of said circular lines being accuratelyattainable by either of the co-ordinate verniers. Additionally, the axisof rotation of the trammel device, because it is common to andinterchangeable with the microscope optical axis, may, by employment ofthe sliding members and verniers, be so located at any desired points onthe drawing as to permit the describing of circular lines about saidpoints and of radii attainable by the sliding members and vemier scaleof th trammel beam.

Having thus described my invention, I claim:

1. A drawing machine or lay-out table comprising a base, a drawing tablesupported on said base, a carriage movable on said base over said table,said carriage having an arm having a scale thereon, a sighting slideguided on said arm and overlying said scale and carrying aline-generating medium, a stationary scale supported by the frame andhaving a sighting slide directly thereover and guided therealong bymeans on said frame, a part of said carriage being adapted to abut saidlast mentioned sighting slide, and each slide having means to clamp itat any desired position on its scale.

2. A drawing machine or lay-out table comprising a base, a drawing tablerotatably supported by said base, a carriage movable on said base overthe table, said carriage having an am having a scale, a sighting slideguided on said arm over said scale and having thereon a scriber disposedclose to said arm and scale, a stationary scale supported by the base,and a sighting slide adapted to be clamped relative to said stationaryscale and movable therealong, said carriage being adapted to be limitedin its movement by said last mentioned slide;

3. A,drawing machine or lay-out table comprising a base, a tablesupported by said base and adapted to receive the material on whichadapted to'be clamped in various positions of adjustment.

6. A drawing machine of the character described comprising a frame, atable on the frame adapted to support the material on which the drawingis to be made, a carriage supported by the frame for movement over saidtable, a scale mounted on said carriage, a slide movable along the scaleon said carriage, and having an opening adapted to receive a scriber anda trammel having a projection releasably pivoted in said opening andcarrying a slide also having an opening adapted to receive a scriber,said openings being of the same diameter.

' 7.'A device of the class described, comprising a support havingthereon a table, a carriage slidable on the support over the table andhaving a scale and a tool-carrying slide having a vernier and movableover and along the scale, a stationary scale on the support, astop-slide having a vemier and movable over and along said stationaryscale, each slide having means by which it can be clamped in anyadjusted position in reference to the scale, and the support andcarriage respectively having means for so guiding its slide as toprevent vertical motion thereof.

8. A device of the class described, comprising a frame slidable on asupport, said frame having an arm pointing toward the operators station,a tool holder slidable on said arm in a direction perpendicular to thedirection of slidingof the frame and in relation to a scale also on thearm, said holder having means for rigidly but releasably holding a tool,a sighting-slide adjustable along a scale fixed on the support at itsfront and at the operators station and parallel with the direction ofsliding of the frame, said slide having means for clamping it at anyadjusted position along said fixed scale, a table on said support belowsaid arm, and means carried by said arm and slide cooperable forreleasably locking the arm to the slide.

9. A device of the class described, comprising a frame movable onparallel ways of a support, a combined tool holder and sighting slideslidable on said frame in adirection perpendicular to the ways, and inrelation to a scale on'the frame and having an opening adapted toreleasably receive a x tool, a sighting slide on said support adjustablealong a scale in a direction parallel to one of said ways and havingmeans to clamp it at any adjusted position in reference to the scale, atable rotatable on said support. at .a level below but close to theunder side of said toolholder slide, said table having peripheralgradu'ations, means on the support for clamping the table in anyposition 'after rotation, and means carried by said frame and slidecooperable for releasably locking the frame to the slide, which movesover the stationary scale.

10. A device of the class described, comprising a support having frontand rear parallel horizontal ways, a frame having widely spaced portionssliding on the rear way, and having an arm having its outer end slidingon the front way, said arm having parallel ways, one at each oppositeside and lying in the same horizontal plane and perpendicular to saidfront and rear ways, a first scale on the top of the arm, a tool holderheld in sliding relation with said ways and against vertical motion andoverlying the scale and having a 4 sighting opening downwardly throughwhich the scale can be viewed, and further having an axially verticalopening close to but disposed laterally of one of the ways of the armand adapted to rigidly hold a tool, means for clamping the tool holderto the arm, an auxiliary way on said support parallel with the front wayand having a scale, a slide overlying the second scale and slidablyconnected with the auxiliary way and having a sighting openingdownwardly through which the scale can be viewed, and having means forclamping it at any adjusted position along the way, and a table .on saidsupport below the arm and close to the opening of the holder forsupporting an element in operative relation to a tool held by theholder.

11. A device of the class described, comprising a frame slidable ona'support, said frame having an arm, a first tool holder slidable onsaid arm, a scale also on the arm, said holder having an opening forrigidly holding a tool, said holder having means for clamping it to thearm, a table on said support below said arm, a second or auxiliary armoverlying said table and having a pivot lug releasably engaged in theopening of said holder to allow horizontal swinging motion of the armover the table, said second arm havin thereon a second tool holderslidable along a scale also on the second arm, said holder having meansfor clamping it 'to the second arm and having an opening of the samediameter as that of the first mentioned opening for rigidly holding thetool, said second arm having auxiliary supporting means which slidablyengages the table to hold the arm parallel therewith, whereby the pivotlug of the second arm can be removed from the opening of the first toolholder, and the tool can be inserted in said opening and whereby theopening of the first tool holder is used for swingingly mounting asecond slidable tool holder, the opening of which can then receive thesame tool.-

12. A device of the class described, compris ing a frame slidable on asupport, said frame having an arm, a first tool holder slidable on saidarm and over a scale also on the arm, said holder having an opening forrigidly holding a tool, said holder having means for clamping it to thearm, a table on said supportbelow said arm, a second or auxiliary armoverlying said in the opening of said holder to allow horizontalswinging motionof the arm over the table, and said second arm havingthereon a second-tool holder slidable along ascale also on the secondarm, saidholder having means for clamping it to the second arm andhaving an opening for rigidly holding a tool, said second arm havingauxiliary supporting means which slidably engages the table to hold thearm parallel therewith.

a support having front and rear parallel horizontal ways, a frame havinga substantially elongated portion sliding on the rear way, and havingextending from a point near one of its ends, an arm having its outer endsliding on the front way, said arm having two parallel waysperpendicular to said front and rear ways, a first scale on the top ofthe arm, a cutting tool holder sliding on the corresponding ways andoverlying the scale and having a sighting opening downwardly throughwhich the scale can be viewed, and further having axially an openingclose to but disposed laterally of one of the ways of the arm andadapted to rigidly hold a cutting tool,'a pair of ways on said supportparallel with and near and in front of the front way and having a scale,a slide overlying the second scale and slidably connected with thecorresponding ways and having an opening downwardly through which thescale can be viewed, and having means for clamping it at any adjustedposition along the scale, and means respectively on the arm and on theslide cooperable for releasably locking the arm rigidly to the slide,and a table on said support below the arm and close to the under side ofthe tool holder for holding an element on which a delineation is to becut.

14. In a device of the class described, a support having a circulartable rotatable thereon, said table having peripheral graduations, saidsupport having a block having thereon an arcuate vernier associated withsaid graduations of the table, a slide on the block movable in anarcuate path and having a window overlying the vernier and graduations,and having a reference line by which to facilitate registration ofvernier and table graduations, means for clamping the slide to the blockin any arcuately adjusted position, said block also having means thereonfor releasably clamping the table, including a clamp-operating elementaccessible at a point near the slide.

15. A device of the class described, comprising a support, a table onsaid support, a frame movable over the table, a scale on said frame, apair of coplanar parallel horizontal ways for said scale, one at eachside thereof, a slide rigidly held by the ways against vertical motion,said slide having a sighting window downwardly through wmch the scalecan be viewed and having a vernier on the margin of the window, and alsohaving means to clamp it to its ways, and having means for releasablybut rigidly holding a'tool against vertical motion and in delineatingrelation to the table, the said ways of said slide 081118 01088 to saidtable.

16. A device of the class described comprising a base having thereon, aframe comprising first and second arms arranged in L-shaped relation, asviewed from above, a pair of tracks front and rear, parallel with therear arm and over 13. A device of the class described, comprising andupon which the arms are respectively slidably guided, and a turntabledisposed intermediately of the tracks and in substantially tangentrelation therewith and over which the -front arm of the frame ismovable, the arms being so arranged in relation to the table that one ofthe arms can be moved to a substantially tangent relation with thetable, and when so I related leave the entire area of the table exposedto view.

. table, one of the arms of the L being parallel with and sliding on therear track and the other arm being perpendicular to and sliding on thefront track and extending toward the operator's station, said arms beingso arranged in relation to the operator as he stands near the fronttrack, and to the table, that when the frame is at one limit positionthe entire area of the table can be visible.

18. A device of the class described comprising a base,'front and rearparallel tracks on the base, a drawing table between said tracks, anL-shaped frame slidable on said tracks over the table, one of the armsof the L being parallel with and sliding on the rear track and the otherarm being perpendicular to and sliding on the front track, said armsbeing thus so arranged in relation to the operator as he stands near thefront track, that when the frame is at one limit position the entirearea of the table can be visible, the last mentioned arm having a scaleon its top arranged lengthwise thereof and having a slide guided on thearm over said scale, said slide having asighting opening, means to clampthe slide, and said slide having means for clamping a tool thereto indelineating relation to the table.

19. A device of the class described having a base, having front and rearparallel slide ways, a frame composed of first and second arms arrangedin L-shaped relation, a first arm being arranged lengthwise of andsliding on the rear way, and the second arm being arrangedperpendicularly to, having its outer and front end sliding on the frontway and extending toward 3 the operator's station, a drawing tabledisposed between the ways and over which the frame moves, the uppersurface of said table being substantially in the same horizontal planeas the tops of the slides, and the bottom of said second arm being closeto the top surface of the table, a scale on the top of the second armtoward the table, and releasable means on the slide engaging with saidannular shoulder to prevent motion of the holder away from the table.

21. A device of the class described, comprising a base having a drawingtable thereon, a carriage on an arm movable over said table, a scale onthe top of the arm, a slide guided on the arm and having means to clampit to the arm, a tool holder removably held in an opening in said slideand having a shoulder which limits motion of theholder in a directiontoward the table, and releasable means on the slide engaging with saidshoulder to prevent motion of the holder away from the table andcomprising a lever, means translatably fulcrumming the lever on theslide, said lever at one side of the fulcrumming means being engagedwith the shoulder, and means at the opposite side of said fulcrummingmeans for applying leverage power to said lever.

22. A device of the class described, comprising a base having thereon acircular rotative drawing table marginally graduated, a support on thebase having a scale with which graduations of the table are adapted toregister, means on the support for clamping said table in relation tothe scale, a lever pivoted to the support and having on its free endclamping elements including a first arm over the table and a second armunder the table, said arms and the pivotal axis of the lever beingsubstantially radially related extendinglengthwise thereof, a pair ofcoplanar 20. A device of the class described, compris ing a base havinga drawing table thereon,,zai carriage on said base having an arm movableover said table, a scale on the arm, a slide guided on the arm andhaving'means to clamp it to the arm, a tool holder rotatably held in anopening in said slide, and having an annular shoulder which limitsmotion of the holder in a direction to the axis of rotation of thetable.

23. A device of the class described, comprising a base having thereon acircular rotative drawing table marginally graduated, a support on thebase having a scale with which graduations of the table are adapted toregister, means on the support for clamping said table in relation tothe scale, said clamping means comprising a lever pivoted to the supportand having at its free end a first arm over the table and a second armunder the table and a floating block on the second arm, said arms andblock being normally disposed out of engagement with the table, andmanual means adapted to simultaneously move the upper arm and block intoclamping relation with the surfaces of the table.

24. A device of the class described, comprising a base having thereon acircular rotative drawing table marginally graduated, a support on thebase having a scale with which graduations of the table are adapted toregister, floating means on the support for clamping said table inrelation to the scale comprising a lever pivoted to the support andhaving at its free end a first arm over the table and a second arm underthe table and a floating block on the second arm, means for limitinglever motion to normally dispose the upper arm and block so that theyareout of engagement with the table, means yieldably urging the clampagainst the limiting on the slide by which slide-securing pressure canbe applied against and substantiallyin the plane I of the ways of thearm, said slide having an opening close to one of the ways of said arm,a

table between the ways, a frame movable over the table on the ways andhaving an arm, said arm having lengthwise thereof, at opposite sides,parallel ways in the same horizontal plane and facing laterally, across-sectionally C-shaped sighting slide on the top of the armoperatively engaged with the ways of the arm, means on the slide bywhich slide-securing pressure can be applied against and substantiallyin the plane of the ways of said arm, said slide having an openingimmediately adjacent one of the ways of said arm, a scriber holderaccurately fitting in said opening, and means on the slide for rigidlysecuring the scriber holder against axial motion in a direction awayfrom said table, the ways and the bottom of said arm being close to butspaced from the table.

'27. A device 'of the class described comprising, a support having frontand rear ways, a rotatable drawing table between the ways, a framemovable over the table on the ways and having an arm extending betweenthe ways and pointing toward and supported on the front way, near whichfront way the operator stands, said arm having lengthwise thereof, atopposite sides, parallel ways i the same horizontal plane and facinglaterally, a cross-sectionally c-shaped sighting slide on the top of thearm having grooves operatively engaged with the ways of the arm, meanson the slide'by which slidesecuring pressure can be applied against andsubstantially in the plane of the ways of said arm, said slide having anopening immediately adjacent one of the ways of the arm, a scriberholder accurately fitting in said opening, and means on the slide forrigidly securing the scriber holder against axial motion in a directionaway from said table, the ways and the bottom of said arm being close tobut spaced from the table.

28. A device of the class described comprising, a support having frontand rear V-shaped ways, a rotatable drawing table between the ways, anL-shaped frame movableover the table and comprising a first arm having adownwardly facing groove slidably engaged with the V-shaped rear wayonly at two widely spaced points and the second arm extending from thefirst arm at a point intermediately of the engaging points of the firstarm with the rear way,- said second arm having its outer. 'end slidablyengaged by a single point of contact with the V-shaped front way, saidsecond arm having lengthwise thereof, at opposite sides, parallelV-shaped ways in the same horizontal plane and having their crestspointing laterally, a cross-sectionally C-shaped venier sighting slideon the top of the second arm having V-shaped grooves operatively engagedwith the V-shaped ways, means on the slide by which slide-securingpressure can be applied against and substantially in the plane of thecrests of the ways, said slide having an opening immediately adjacentand substantially tangent to one of the v-shaped ways of said secondarm, a scriber holder accurately fitting in said opening and means onthe slide for rigidly securing the scriber holder against axial motionin a direction away from said table,

the ways and the bottom of said second arm being close to but spacedfrom the table.

OSCAR C. HEDIN.

